Thermostatic device



Au 11, 1931. w, c. LIN

DEMANN ..|-:'r AL msnlosnnc DEVICE Filed 0ct. 1o, 24

l II [7/ [Ill/I111 [III/l I Patented Aug. 11, 1931 UNITED STATES PATENT OFFICE WALTER C. LINDEMANN AND EDWIN A. RUTENBER, OF MILWAUKEE, WISCONSIN,

ASSIGNORS TO A. J. LINDEMANN &

HOVERSON COMPANY, OF MILWAUKEE, WIS- consnr, A coaronarron or WISCONSIN ,4 rnnnmosra'rrc nnvrcn Application'filedoctober 10, 1824.' serial at. 742,748.

The improvements relate to devices for automatically controlling the temperature of ovens and other heating and cooking devices, and primarily todevices of this character in which the heat is generated electrically. They are in thenature of improvements in the construction and arrangement of the apparatus described and shown in our copendi-ng a plication for patent'filed April 24th, 1924, erial Number 634,246.

The improvements are illustrated in the accompanying drawings, in which Figure 1 is a side elevation of a thermostat device embodying the improvements;

, Figure'2 is a longitudinal vertical section thereof;

Figure 3 is a front view of the same with the cover carrying the adjusting cam removed; and

Figure 4 is an inside view of the cover with the cam mounted therein.

The instrument, as illustrated, is mounted in the hollow wall 1 of an oven or the like, and is connected with an electrical circuit by means of conductor wires 2, 3, for the purpose of energizing and de-energizing' a heatin element in the circuit, or operating a suita le switch for that purpose. These wires are connected with terminals 4 and 5 extending into av horizontall arranged vessel 6, or-glass or other insui ating material, and have their extremities in close proximity inside the vessel so that when the vessel is swung laterally a drop of mercury 7 will gravitate from one end to the other thereof and make or break the circuit and thus control'the heater. Suitable electricalcontacts may be provided for the wires 2 and 3, if

desired, so that when the instrument is placed in position the circuit will be co pleted by the engagement of these contact devices with other contacts on the oven.

The bottle 6 is hung from a shaft 8 by means of a U-shaped hanger 9, in which it is mounted, and as the hanger is fixed to the end of the shaft 8, and the shaft 8 is rotated by a thermostatic helix 10, the bottle is caused to swing or oscillate by the tem-- perature of the oven, and the current to the heating element thus thermostatically being held tightl I shaft controlled. One end of vthe thermostatic coil 10 is secured the other end to the hollow bar 12, in which the shaft 8 rotates, at 13, so that expansion and contraction in the metallic band of which the thermostatic coil is made causes rotation of the shaft, and consequently oscillation of the vessel 6. The hollow rod 12 is inturn mounted in the tube 14 fixed in the frame of the oven, and on the opposite ends of which the protecting cage 15 and the housing cup '16 are threaded.

In order to determine the temperature at which the electrical circuit shall be broken through the action of the thermostatic coil the following means are provided. A disc or collar 17 with jaws 18 is secured on the hollow rod or sup orting member 12,'by

etween the shoulder 19 near the end of t e rod and a serrated disk 20 keyed on the end of said rod 12. This connection permits the maker to adjust the disk 17 on the hollow rod 12 to compensate for slight variations in the heat conductivity of the ovens or the heating capacity of the heating units, or other variations and thus to adjust slightly the instrument to a given temperature. Small holes 21 in the disk or collar 17 are provided so that the end of a key may be inserted therein with a pin or flange enga 'ng between the teeth of the disk 20 and the key turned to move the said disk 17. The jaws of the disk 17 receive a pin 22 on an arm 23 of the loose collar. 24 mounted to oscillate "on a stub 25, while another arm 26 on the collar 24 has a pin 27 which engages a cam 28 on the inside of the cap or cover .29, so that when the said cap or cover is rotated the sleeve 24 and its arms, acting after the manner of a bell crank will oscillate the collar 17, and through it the 8, thus canting the vessel 6 slightly. In this manner, when the cover is rotated in counter clockwise direction, the vessel and the coil are moved slightl in the same direction and when it is move clockwise the said parts are moved correspondingly in that direction. The rocking of the shaft 8 coun-- ter clockwise tilts or cants the bottle 6 so that a greater expansion of the C011, requirto the shaft 8 at 11, and

ing a higher degree of heat, is necessary to cause the drop of mercury to gravitate to the right handend of the bottle and break the circuit, and the rotation of the shaft in the opposite direction has the opposite effect. The instrument is normally set at the lowest operating temperature, and the collar 17 and parts operated thereby are held in normal position by the spring 30 on the collar 24, which has one end bearing a ainst the inner wall of the housing 16 and the other turned around the arm 26, the movement of the said collar being against the tension of the spring, and the action of the spring tending at all times to return it and the parts operatively connected therewith to normal position. A tension spring 41 with one end connected with 17, and the other to the housing may be used in place or in connection with the spring 30 for the same purpose. The disk 28 has a projection 31 on its periphery providing stops at 32 and 33 for the pin 27, and acting to limit the rotation of the cover 29 to a little less than 360. Separate pins or lugs may be used if desired, for this purpose.

On the outside of the cup housing is an index 34, and on the flange 39 of the cover are scale markings 35 to indicate various temperatures, in this instance from 250 to 500 F. The cover is provided with an outer cap 36 with a burred or milled edge whereby it may be rotated by hand, and this outer cap is made of some substance having the insulating and poor heat conducting qualities of hard rubber. It will therefore be seen that the operator may by turning the cover to a point where the desired temperature is indicated tilt the bottle 6- through cam 28, bell crank 24;, etc., collar 17 and shaft 8-so that a greater or lesser degree of expansion of the thermostatic coil will be required to move it to a sufficient extent to cause the mercury to gravitate away from the terminals and break the circuit, this degree of expansion in each case being that produced by the desired temperature.

It will be seen that the shaft 8 rotates in the hollow rod 12, but that there is a sufiiciently rigid connection through the coil to permit it to be turned thereby when the said rod is oscillated by the annular disk or collar 17. It will also be seen that this collar 17 is free to move on the shaft 8, and may also move against the friction produced by the clamping action of the toothed disk 20 which holds it against all normal strains preventing rotary movement relative to the rod 12, this disk 20 being keyed on the end of said rod 12.

In order to provide for the securement of the cover 29 on the cup housin 16, and at the same time permit its rotation thereon,

. an annular groove 37 with diametrically op- 38 is formed on the interior of the cover, and spring tongues 40 are stamped out of the walls of the cup 16, and extend intermediate their ends slightly above the surface thereof. This arrangement permits the removal of the cover by pressing on the tongues with the fingers while exerting a pull thereon, but holds the cover securely in position and provides an accurate guide for its rotary movement.

The details of construction and the particular arrangement herein described and shown may be varied, and parts may be added to those specified in order to adapt it to certain uses, or for other purposes, all without departing from the scope of the invention.

What we claim is:

1. A thermostatic device for controlling an electric circuit comprising a heat operated element including a thermostatic metallic coil, a circuit closing device including a tiltable vessel, terminals and a fluent conductor therein, means intermediate said circuit closing device and said heat operated element for operating the former to break the circuit by the heat expansion of the latter and means for varying the point at which the said intermediate means will cause circuit breaking movement of said device posite openings without changing the relative positions of' said device and said element.

2. A thermostatic device for controlling an electric circuit comprising a heat operated element including a thermostatic metallic coil, a circuit closing device including a tiltable vessel, terminals and a fluent conductor therein, means intermediate said circuit closing device and said heat operated element for operating the former to break the circuit by the heat expansion of the latter, means for varying the point at which the said intermediate means will cause circuit breaking" movement of said device without changin the relative positions of said device an said element and means for adjusting the relative positions of said intermediate means and the said varying means.

, 3. The combination with a thermostatic device of a housing, a cover mounted to rotate on said housing and connections between said cover and thermostatic device whereby rotation of the cover adjusts the said device to operate at different temperatures,"and a connection between said housing and cover comprising an annular groove on one and a spring projecting member on the other, one of said housing parts having an openin therein giving access to the spring pro ecting member whereby it may be depressed to permit-removal of the cover.

4. A thermostatic device for controlling an electric circuit comprising a heat operated element including a thermostatic metallic coil, a switch including a tiltable vessel, terminals and a fluent conductor therein, means for communicating movement of the coil to the vessel to open and close the switch comprising a rotatable rod, connections between the rod and coil and between the rod and vessel, and means for varying the point at which switch-opening movement is imparted to the switch by the coil comprising a rotary disc and means for rotating it and for retaining it in various positions of its rotary movement and means for indicating the movement of the disc in terms of temperature.

5. A thermostatic device comprising a movable supporting member, a movable contactor, means including a thermally responsive element operatively connecting said member and contactor, means for movin said member and contactor as a unit, said last named means being adjustable relative to said contactor and to said member.

6. A thermostatic device comprising a movable supporting member, a movable contactor, means including a thermally responsive element operatively connecting said member and contactor for moving said contactor relative to said member, a cam operated arm frictionally secured to said member for moving said member and contactor as a unit, said arm being ad'ustable relative to said contactor and to said member.

A thermostatic device comprising a movable supporting member, an actuating shaft supported by said member, thermal means connecting saidmember and shaft, a contactor supported on said shaft comprising fixed electrical terminals and a conducting body movable therebetween a member for moving said member and shait in unison, said last named member being adjustable relative to said first named member and shaft, and a toothed disc fixed to said supporting member for moving same relative to said last named member.

Witness our hands this 7th day of October, 1924, at the city of Milwaukee, in the county of Milwaukee, State of Wisconsin.

WALTER C. LIN DEMANN EDWIN A. RUTEN BER.

DISCLAIMER 1,818,563.Walter C. Lindemimn and Edwin A. Rutenber, Milwaukee, Wis. THER- MOSTATIC DEVICE. Patent dated Aug. 11, 1931. Disclaimer filed July 2, 1945, by the assignee, Automatic Products Company. Hereby enters this disclaimer to claim 1 of said patent.

[Ofiicz'al Gazette August 7, 1.945.]

DISCLAIMER 1,818,563.-Walter O. Lindemann and Edwin A. Rutenber, Milwaukee, Wis. THER- MOSTATIC DEVICE. Patent dated Aug. 11, 1931. Disclaimer filed July 2, 1945, by the assignee, Automatic Products Company. Hereby enters this disclaimer to claim 1 of said patent.

[Oflicial Gazette August 7, 1945.] 

